Wave Analysis in Ultrasonic Inspection using Ultrasonic Visualization Method

材料中的超声波受微观组织、缺陷、颗粒、夹杂物等因素的影响，在传播过程中会改变接收波的波形。然后，对接收到的回波进行波形分析，作为材料无损评价的重要步骤。然而，由于转换波分析只利用入射波和接收波，不能对传播过程中的波形进行完美的监测，也不能很好地解决测量装置依赖的影响。本文应用光弹超声可视化系统对声学性能与钢结构相似的玻璃模型试件进行了波形分析。该方法可以估计玻璃模型中各种超声传播状态下的波形，并将光弹超声可视化方法估计的波形与换算方法估计的波形进行了比较。结果表明，当缺陷回波幅度较弱时，可以从光弹超声可视化图像中估计出传播过程中各个状态下的波形。然而，当缺陷回波的幅度较大时，由于所用图像处理系统动态范围较窄，估计的波形会发生变形。

Ultrasonic wave in materials is affected by microstructures, flaw, grain, inclusions and so on, and the wave form of received wave is changed during propagation. Then, wave form analysis of received echo has been considered as the important procedures for non-destructive materials evaluation. However since conversional wave analysis has used only incident wave and received wave, perfect monitoring of wave form in propagation could not be made and the effect of measurement setup dependence remain unsolved. In this report, photoelastic ultrasonic visualization system is applied to estimate the wave form analysis in the glass model specimen whose acoustic properties is similar to steel structures. This method can estimate the wave form at every ultrasonic propagation state in glass model.Estimated wave form by photoelastic ultrasonic visualization method is compared to the one by conversional method. As the results, wave form could be estimated from photoelastic ultrasonic visualization image at every state in propagation when the amplitude of the flaw echo is weak. However when the amplitude of the flaw echo is high, estimated wave form deformed because of the narrow dynamic range of the image processing system used.